Ernesto was persuaded. Then he proposed a wager: he bet his
companions that the underpants he was wearing, the only ones he had owned for
the last two months, would stand up by themselves. ‘Guevara took off his
trousers’ he remembered. ‘Before our eyes was a piece of underwear that looked
like a bricklayer’s work pants, the material was so stiff and its colour so
incredible. He removed this also and we had to give up. Guevara had won the
bet. His shorts stood upright and their owner promised that he would soon teach
them to mark time.’

And, as we can see, clear militarist tendencies. That from
Alex von Tunzelmann’s Red Heat.